The present invention particularly refers to a rotary irrigation minisprinkler comprising a body mountable to a source of pressurized water (pipe) and having an axial bore with an inlet and an outlet formed as a water jet nozzle. The minisprinkler further comprises a rotor mounted for free rotation opposite the nozzle. The rotor has one or more water conduits extending generally radially with some curvature in the plane of rotation. The conduits accept the water jet from the nozzle and direct it to exit radially. The water passing through the curved conduits imparts a torque to the rotor, thereby providing for the rotation of the rotor and the distribution of the exiting jet in a circular area around the minisprinkler.
In most of the conventional sprinklers, the rotor is supported at one end in the body of the sprinkler, and at the other end, by an, element such as a bridge or a spider connected to the body, with the water jet exiting between the two ends. The bridge however intersects the path of the water jet. Examples of this design are disclosed in U.S. Pat. No. 4,583,689.
To avoid the use of a bridge, it has been suggested to provide the rotor with a long pin coaxial with the axis of rotation and received in the water jet nozzle in the sprinkler body. Such bridgeless arrangement is also disclosed in U.S. Pat. No. 4,583,689. Another bridgeless design is disclosed in U.S. Pat. No. 5,984,203 where the rotor of the sprinkler is supported in the outlet end of the nozzle, on a relatively short bearing. U.S. Pat. No. 6,016,972 describes a minisprinkler where the water jet nozzle is elongated and serves as an internal axis for the rotor which is slipped over the nozzle.
The minisprinkler 866 Mini Compact of Ein Dor has a compound rotor consisting of two parts: first, a thick shaft with an annular protrusion and an open channel notched in the shaft and curved in the meridional plane, and second, a wing with a skewed vane. The shaft is inserted rotatably in a bore in the sprinkler body, from the inside, so that the annular protrusion abuts the bore internal edge, and is fixed therein by press-mounting the wing over the shaft end protruding outside the bore. A water jet exits from the nozzle of the minisprinkler, enters the curved shaft channel and leaves it in radial direction. Then the jet impinges onto the skewed vane of the wing and is deflected tangentially, thereby creating a tangential force on the wing to turn the rotor.